DescriptionNanorana parkeri is a small frog that lives in the Tibet plateau southwest of China. Males of have a snout-vent length ranging from 40 – 51 mm. Females have a snout-vent length ranging from 39 – 58 mm. The snout is blunt and protrudes out slightly. The head width is longer than the head length. The nostrils are close to the eyes and the distance between the nostrils is larger than the eye diameter. Nanorana parkeri does not have tympanums or tympanic rings (Fei et al. 2009).

The limbs are relatively short compared to the body size. The forearms are shorter than half of the body length. The fingers are slender and round and the tips are also round. The relative finger lengths are III = I > II > IV. The subarticular tubercles are small and clear, and more obvious under the third finger than all other fingers. The inner palmer tubercle is very obvious whereas the outer palmer tubercle is much smaller and less obvious. The hind-limbs barely reach the front of the shoulder when appressed to the body. The heels meet or overlap slightly with each other when pressed to the body at right angles. The feet are longer than the shins. The toes are slender with slightly swollen tips. The relative toe lengths are IV > III = V > II >I. There is well developed webbing between the toes and small, indistinct subarticular on the toes (Fei et al. 2009).

The skin is rough, with an exception of the head. There is no dorsal lateral fold but there are 5 - 10 rows of regularly shaped tubercles with fine spines scattered in-between the tubercles (Fei et al. 2009).

Nanorana parkeri is the most similar to the two other species of the same genus: N. pleskei and N. ventripunctata. Nanorana pleskei is slightly smaller. Males of N. pleskei are around 32 mm long and females are around 36 mm long. Nanorana pleskei has a small tympanum and clear tympanic ring. The subarticular tubercles are indistinct under both the toes and fingers of N. pleskei. Nanorana parkeri has dark stripes on the dorsal surface while N. pleskei has oval-shaped markings with clearly defined edges. Nanorana parkeri also has grayish brown speckling on the belly that N. pleskei does not possess.
Nanorana ventripunctata is about the same size as N. parkeri. However, the subarticular tubercles are apparent and distinct under all fingers and toes of N. ventripunctata. Speckling on the belly of N. ventripunctata is darker than speckling on the belly of N. parkeri. Nanorana ventripunctata also has irregularly shaped and arranged marks on the dorsal surface that differ from the dark-colored stripes on the dorsal surface of N. parkeri (Fei et al. 2009).

In life, the dorsal surface of N. parkeri is olive green with dark brown or black stripes. There is a dark brown stripe starting from the tip of the snout to the end of the temporal fold. The belly is brownish yellow or grayish white, with scattered gray and brown speckling. The iris is bicolored, brownish green on the top half and tea-leaf brown on the lower half. In preservative, the dorsal surface is grayish brown or dark brown, clear dark-colored stripes. The belly is grayish white or yellowish white (Fei et al. 2000, Fei et al. 2009).

Sexual dimorphism is present in Nanorana parkeri. Males have stronger forelimbs with dark brown nuptial spines on the first and second fingers. Nuptial pads are present on the base of the first finger, and some males have it on the third fingers. Males also have fine brown spine clusters on the chest, showing an upside-down “V” pattern. Some males have spines on the inside of the upper arm. Vocal sacs are absent males (Fei et al. 2009).

Life History, Abundance, Activity, and Special BehaviorsOn sunny days, N. parkeri is found hiding in the grass, muddy caves, and under the rocks close to a water source. Only a few individuals are active during the day. Most individuals are active only after sunset. Nanorana parkeri are more active on rainy or cloudy days and can be found on the ground or the surface of rocks. When disturbed, N. parkerijump directly into the water. In general, adults of N. parkeri are inactive (Fei et al. 2009).

Nanorana parkeri has a relatively long breeding season, starting at the beginning of May and lasting until the end of August. The peak breeding time is May and June. During the breeding season, N. parkeri is found in pairs of males and females. During non-breeding seasons, N. parkeri is found in separate groups of males and females (Fei et al. 2009).

Tadpoles are active during the day and more active at night. Tadpoles are often found swimming in-between water weeds at the depth between 3 – 10cm. Fewer tadpoles are found in deeper water (Fei et al. 2009).

Trends and ThreatsThe overall trend is stable and the species has a threat status of "Least Concern" on the IUCN Redlist. There are no known major threat to N. parkeri, however, overgrazing is identified as a potential threat (Fei et al. 2004).

Possible reasons for amphibian decline

Intensified agriculture or grazing

CommentsThe species authority is: Stejneger, L. (1927). “A new genus and species of frog from Tibet.” Journal of the Washington Academy of Sciences 17: 317-319.

According to analysis based on ancestral traits, the most closely related sister species of Nanorana parkeri are N. pleiski and N. ventripunctata (Che et al. 2010).

Geographic genetic structure is present within Nanorana parkeri with western and eastern population being highly differentiated according to the results based on pairwise mean relative divergence and absolute sequence divergence analysis of the whole genome of 63 individuals (Wang et al. 2018).

Nanorana parkeri was named by Stejneger after Dr. H. W. Parker, in recognition of his help in clearing up important points connected with the investigation (Stejneger 1927). In Chinese, this is commonly referred as “Gao Shan Wo Wa” (Xizang Plateau Frog) (Fei et al. 2000).

This species was featured as News of the week on 21 May 2018:

One of the first frogs to have its whole genome sequenced is Nanorana parkeri, a Tibetan frog that breeds at elevations from 2,800 m to almost 5,000 m, making it perhaps the highest elevation frog. A research team has used availability of its genome to study variation along geographic and elevational gradients (Wang et al. 2018). Genomes were obtained from 63 individuals and used to study adaptation and species formation. Selection was detected in 579 highly divergent genomic regions, involving 365 genes in 51 functional classes. High altitude adaptation was evidenced in genes associated with blood circulation, response to hypoxia and UV radiation. Such adaptation plays a significant role in maintaining and driving continued divergence, even leading to reproductive isolation. The paper opens a new era in the study of genomics of natural populations of amphibians (Written by David B. Wake).

References

Che, J., Zhou, W.-W., Hu, J.-s., Papenfuss, T.J., Wake, D.B., Zhang, Y.-P. (2010). ''Spiny frogs (Paini) illuminate the history of the Himalayan region and Southeast Asia.'' Proceedings of the National Academy of Sciences of the United States of America, 107, 13765–13770. [link]